Characteristics of the cytomictic channel formation in Nicotiana tabacum L. pollen mother cells

New insights into cytomixis: specific cellular features and prevalence in higher plants

“…3b, channel 3) and, on the other, de novo (Fig. 3b, channel 2) on the cell wall regions lacking any plasmodesmata (Wang et al 1998;Yu et al 2004;Mursalimov et al 2010).…”

“…Despite that we regard the term "cytomixis" only as the migration of nuclei, the possibility of migration of the cytoplasm and cell organelles, such as mitochondria and plastids, through CCs has been also demonstrated by the example of microsporocytes (Feijo and Pais 1989;Wang et al 2006;Mursalimov et al 2010). The cytomictic migration of plastids attracts a special attention, since it has been repeatedly demonstrated that the plastids carrying selective traits can migrate between cells of vegetative tissues at the zone of transplant fusion (Stegemann and Bock 2009;Thyssen et al 2012).…”

“…Their emergence in the cell wall allows the nuclei and other organelles to migrate from one cell to another. Unlike plasmodesmata, CCs have no internal structure, such as desmotubules and, as a rule, CCs are considerably larger than plasmodesmata; the CC diameter ranges from 50 to 3,500 nm (Heslop-Harrison 1966;Wang et al 1998;Wang et al 2002;Mursalimov et al 2010). In addition, CCs may occupy over 25 % of the cell surface (HeslopHarrison 1966).…”

“…3d), which covers cells until the tetrad stage; in this process, the primary CCs disappear (Wang et al 2002;Mursalimov and Deineko 2012). However, it has been shown that secondary CCs can be formed in the callose wall and the specific organelles-spherosome-like vesicles, containing the enzyme callase-are involved in this process (Mursalimov et al 2010;2013). These organelles release their content into the cell wall, thereby locally destructing callose and forming the secondary CCs, which provide for cytomixis during all meiotic stages, including the late stages (Fig.…”

“…According to one of the hypotheses, the CC emergence is determined by the need in the contact between developing microsporocytes for synchronization of divisions and exchange with nutrients (Milyaeva 1965;Heslop-Harrison 1966;Mursalimov et al 2010). It is reasonable to regard CCs as the ways for exchange with nutrients and informational molecules.…”